The present invention relates generally to ink jet printing, and, more particularly, to protection of ink jet images printed on print media against oxidation by ozone.
Oxidation of ink jet images printed on print media by ozonation is becoming more recognized as a problem, now that more pressing issues, such as water fastness and smear fastness, have been largely resolved. The problem of ozonation is particularly significant in urban areas where there are large concentrations of ozone from pollution, e.g., Los Angeles and Denver (during the summer months). That dyes and pigments react and thus decompose from ozone is a well-established fact.
Preventing oxidation by ozonation has not, however, been the subject of much investigation to date. Thus, there have been no prior solutions to this problem, to the best knowledge of the present inventor.
Thus, there is a need for preventing oxidation by ozonation of ink jet images printed on print media.
In accordance with embodiments disclosed herein, a method of protecting colorants printed on print media against ozonolysis is provided. The method comprises:
(a) providing a first reaction product comprising the reaction of a phenylenediamine or derivative thereof with a silane; and
(b) reacting the first reaction product in the presence of a water-free solvent with silica groups to form a second reaction product.
Further in accordance with other embodiments disclosed herein, a reaction product is provided resulting from the reaction of (1) the first reaction product comprising the reaction of a phenylenediamine or derivative thereof with the silanol to form a phenylenediamine silane (or phenylenediamine silanol) and (2) silica groups on a substrate.
Additionally, in accordance with yet other embodiments disclosed herein a method of printing an ink on a print media is provided, where the ink contains at least one colorant susceptible to ozonolysis. The method comprises:
(a) providing a first reaction product comprising the reaction of a phenylenediamine or derivative thereof with a silane;
(b) reacting the first reaction product in the presence of a water-free solvent with silicic acid groups on the silica gel coated media to form a second reaction product, namely, a PDA-derivatized silica gel; and
(c) printing the ink on the print media.
The anti-ozonant employed in accordance with the teachings herein is covalently attached to the particles of PDA-derivatized silica gel in the media and cannot escape or evaporate away.
The use of phenylenediamines, or derivatives thereof, solves the problem of the fading of dyes on porous media by ozone pollution.